1. Field of the Invention
This invention relates to a mechanism for raising and lowering vehicle window panes by means of a cable. Such mechanisms generally include a carrier element attached to the window pane, to which carrier element the cable is attached, and a drive mechanism for moving the cable to thereby raise or lower the window.
2. Background of the Invention
The cable of a cable window winding mechanism is generally subjected to a variety of stresses which result from the configuration of the cable path.
Probably the most prominent stress on the cable is the tensile stress. The tensile stress is a function of the weight of the window pane, the friction conditions in the guides of the window pane, and the type of cable guides. However, in addition to the tensile stress, a bending stress, as well as a surface pressure also can typically occur at the guide pulleys.
The magnitude of the bending stress is, in particular, a function of the diameter of the guide rollers, which can be, for example, guide pulleys, and of the diameter of the cable drum of the drive mechanism. In addition, the style of the cable can also determine its bending stress.
The magnitude of the surface pressure, on the other hand, is a function of the respective tensile load and the contact surface in the cable grooves of the cable drum or of the guide pulleys. Likewise, the style of the cable can also determine its surface pressure.
Moreover, the cable can also be stressed by torsion and friction, whereby the latter typically occurs when rigid guides or deflection guides are used.
In cable window winding mechanisms of the prior art, one-piece, closed cable loops or cable loops consisting of several cable segments are generally used, whereby the selection of the cable quality is typically determined as a function of the anticipated maximum load, and the entire cable, or pieces thereof, are generally made of a material which can withstand this anticipated maximum load. Accordingly, cables of the prior art have therefore, always been oversized in segments of the cable to which only low stresses are applied.